Following the vote, analysts predict at most two or three of the state's nine House Democrats could see significant backlash. Only one, Suzanne Kosmas of New Smyrna Beach, seems seriously vulnerable.

A more significant effect could come if candidates for other offices are pressured to take a stand on the health care bill.

There's no better example of why Florida Democrats could escape the GOP wrath than Tampa's Rep. Kathy Castor. She's been a leading health care reform advocate from the outset, but she has little to fear at the polls.

"In this district I don't see her being vulnerable," said University of Tampa political scientist Scott Paine, a Democrat and a former Tampa City Council member.

The reason, ironically, stems from Republican efforts early this decade to maximize the number of GOP Congress members from Florida.

In drawing congressional districts, the GOP-led state Legislature crammed Democratic voters into as few districts as possible, including Castor's.

That made the neighboring districts safe for Republicans, but it also made the occupants of the Democratic districts tough to dislodge.

"ANYBODY BUT CASTOR!!" howled a commenter on the conservative RedState blog in January, who identified herself as a resident of South Tampa, the heart of Castor's district. "Kathy Castor D11-FL Can you hear us now? You are next!"

No Florida Congress member is more strongly identified with the health care bill. Castor helped draft important parts of it, and plans to attend President Barack Obama's bill signing ceremony Tuesday.

A town hall meeting she attended in August on the subject made national news when it dissolved into bitter shouting and minor violence.

But so far, no Republican is mounting a serious challenge to her.

Six Republicans have filed, including Eddie Adams, who has already lost to Castor twice, by vote margins of more than 2-1.

Another, Mike Prendergast, may be gathering significant support among local Republicans, but is a political unknown who will have to build his challenge from scratch.

Meanwhile, Castor starts with almost $300,000 in her campaign account. But her strongest weapon is the voting roll of Tampa's 11th Congressional District.

In the 2002 redistricting, the Florida Legislature, seeking to ensure elections for Republicans C.W. "Bill" Young and Katherine Harris, took Democratic-voting, inner-city precincts from their districts, in Bradenton and south St. Petersburg, and put them into District 11, then represented by Jim Davis.

The result: In 2008, District 11's 389,190 voters were 50 percent Democrats, 24 percent Republicans and 26 percent minor party and no party voters.

In 2008, Obama won the district 2-1; in 2004, John Kerry beat George Bush there by 17 points.

Hillsborough County GOP Chairman Debbie Cox-Roush said her e-mail inbox overflowed this morning with Republicans urging action against Castor.

"We must act today in order to preserve our freedoms!" said a message to GOP supporters from Prendergast.

But even Cox-Roush acknowledges Castor will be tough to beat.

"I think there will be a backlash," she said. Asked whether it could affect Castor, she said, "A year ago I would have said 'no.' But in this political climate, I won't say 'no.'"

Castor herself doesn't sound worried.

"I think it will fade as an issue," she said. "I think the primary issue will continue to be the economy and jobs."

Democrats most likely to be vulnerable are in districts that weren't set up as Democratic in the 2002 redistricting, Kosmas and Ron Klein of Boca Raton, and Alan Boyd of Monticello, who holds a conservative, Panhandle district.

In those areas, noted retired University of South Florida political scientist Darryl Paulson, Republicans can use what may be their strongest weapon â?? a fired-up base.

Polls, Paulson said, are showing Republicans more eager to vote in 2010 than Democrats by double-digit margins.

• Kosmas, a freshman, unseated the scandal-plagued Tom Feeney in 2008 to win in a GOP-leaning district. She switched her vote on the bill from "no" last year to "yes" Sunday night. Kosmas faces several potentially serious Republican challengers, including state Rep. Sandy Adams of Orlando.

• Klein narrowly unseated Republican Clay Shaw in 2006, but the district is trending Democratic. His leading challenger so far is Allen West, a retired Army officer and Bronze Star winner who's popular among conservatives and tea party Republicans â?? but Klein beat him 55-45 percent in 2008. "The question for West is whether anti-incumbent fever is high enough to make a difference this time," said Brian Crowley, a Palm Beach political consultant and former journalist. "Right now, I think Klein wins."

• Boyd switched his vote, as Kosmas did, but is known as a moderate who fits well in his district, which he has held for six terms. So far, his most serious challenge looks like it may come in the Democratic primary, where he faces a comparative liberal, state Sen. Al Lawson of Tallahassee.

University of South Florida political scientist Susan MacManus considers Kosmas the only really vulnerable House member. But she thinks the health care controversy could have a greater effect on non-Congressional candidates.

"Some of them would rather that not be the focus," she said.

Chief Financial Officer Alex Sink, running for governor, has resisted GOP attempts to draw her into the health care debate; U.S. Rep. Kendrick Meek, running for the U.S. Senate, may have to defend his support for it.

Paine, of the University of Tampa, said he believes whether these or any Democrats face serious challenges could depend on how the issue is framed.

Polls, he said, showed, "Most Americans wanted health care reform, and most wanted most of the major elements of this bill. They opposed the bill itself, but by close margins."